[An experimental and clinical study of thin-slice high-resolution CT for lung detail]

The clinical usefulness of thin-slice high-resolution CT in the diagnosis of the chest was assessed by (1) experiments using a phantom and an inflated fixed lung (Heitzman's method), (2) evaluation of the CT delineativity of the bronchi and major fissure and (3) clinical examination of patients with diffuse pulmonary diseases. 1) In a phantom experiment using catheters, 10 mm-thick slice scan showed the 6 catheters as a single faint line. By 1.5 mm-thick slice scan, the catheters were defined as 6 separate lines. The profile images suggested that 1.5 mm-thick slice scan enables delineation of more minute details of structures. 2) In an experiment using an inflated fixed lung, 1.5 mm-thick slice scan produced more informative images that resembled macroscopic or soft X-ray images. 3) By 1.5 mm-thick slice scan, the subsegmental bronchi of both the right and left lobes were identified in most cases, while identification was possible in only half the cases by 10 mm-thick slice scan. 4) By 10 mm-thick slice scan, the sub-subsegmental bronchi were not identified in most cases. However, identification was possible in approximately half the cases by 1.5 mm-thick slice scan. 5) By 1.5 mm-thick slice scan, the major fissure was delineated as a linear shadow in most cases. It was hardly recognizable by 10 mm-thick slice scan. 6) In diffuse pulmonary diseases, 1.5 mm-thick slice scan allowed more minute visualization of the patho-morphological changes compared to 10 mm-thick slice scan. 7) Thin-slice high-resolution CT is thus expected to contribute to pathological analysis and more accurate diagnosis of pulmonary diseases.